The present invention relates to a condensate drain for an air conditioning system.
Air conditioning systems normally have a condensate drain for draining away liquid water which condenses when air is cooled. In many systems, the blower which blows conditioned air into the conditioned chamber, such as a vehicle cab, is down stream of the condensate drain, so that the drain is exposed to a negative air pressure. The negative pressure in the drain line can cause air and dirt to be sucked into the system. Sucking dirt into the system lowers performance and life of the blower and sends dirt into the conditioned chamber. To prevent dirt from being sucked into the system, some systems employ a trap or a loop in the drain line to form a water trap, while others use a simple check valve. However, such loops or valves often times result in plugging of the drain line due to insufficient water flow to flush dirt out of the line. Such plugging can cause water to flow onto and damage operator enclosure floors, motors and filters.
Accordingly, an object of this invention is to provide an air conditioning system condensate drain which is unlikely to plug.
Another object of this invention is to provide an air conditioning system condensate drain which does not draw exterior dirt into the drain.
These and other objects are achieved by the present invention, wherein an air conditioning system has an air duct, an air conditioning unit in which condensation forms and a condensation drain outlet. A drain system includes a fitting having a first tube, a second tube and a third tube joined together at a common intersection. A water drain line communicates the first tube with the drain outlet. An air line communicates pressurized air from the air duct to the second tube. The third tube is communicated with the environment. The second and third tubes are oriented so that air and condensed water flow away from the intersection and through and out of the third tube. Preferably, the third tube has a down stream end which is not above its upstream end, and the first tube has a down stream end which is not above its upstream end. The tubes may form a T-shaped or a Y-shaped fitting. The second tube and third tubes may extend substantially horizontally while the first tube may extend substantially vertically upwardly.